Water-tube boiler



Jan. 20, 1931. H. E. YARROW WATER TUBE BOILER Filed Sept. 19. 1927 2Shoots-Sheet 1 java Zar r0 7a" 715' garr'ow 1 Patented Jan. 20, 1931UNITED STATES HAROLD EDGAR YARROW, 0F. GLASGOW, SCOTLANDWATER-TUBEVBOILER Application filed September 19, 1927, Serial No.220,442, and in Great Britain November 18, 1926.

In order to protect the casing of the com bustion chambers of water tubeboilers from excessive heat, ithas been proposed entirely to close thefour sides of the chamber by the generating tubes, and for this purposeauxiliary drums have been provided parallel and adjacent to the lowerside walls, from which drums tubes extend to an upper steam and waterdrum.

According to the invention, one or more sets of these auxiliary tubesforms at each side wall a single bank of tubes at the auxiliary drumsand a bank of tubes of two or more rows in depth at their upper endswhere they enter the steam and water drum. 7

For this purpose the auxiliary tubes con necting the auxiliary drumswith the steam and water drum are arranged in groups which arerelatively displaced in relation to the axes of the auxiliary drums, andare arranged fan-wise, converging from each aux iliary drum towards thesteam drum, so that, while the tubes at their lower ends form a singlerow, the tubes of adjacent groups overlap towards their upper ends toform a double or multiple row.

In the accompanying drawings which represent an arrangement of auxiliarydrums and water tubes according to the invention-- Fig. 1 is a verticalsection of a Yarrow type boiler embodying this arrangement, v

Fig. 2 a partial sectional plan on line 2-2 of Fig. 1, and

Fig. 3 a transverse section on line 33 of Fig. 1 of one example. i

In these figures, A is the steam and water drum and B, B the water drumsof a Yarrow type of water tube boiler. C and C are additional. drumsextending at right angles to the drums B, B and forming the base of thetriangular. disposition of the con'ibustion chamber as viewed fromeither side.

Straight tubes D extending from the drums C, C to the upper drum A areuniformly spaced along the length of the drums C, C" and spread in afan-like disposition outwards from the upper drum where they are locatedin the lower portion of the upper drum in line with the main generatingtubes of the boiler.

The tubes D are arranged in groups E to E, which are relativelydisplaced with reference to the longitudinal axes of the drums C, C Asshown in Fig. 2, theouter section E of tubes on the left hand side isdisplaced to one side of the axis, the nextrsection E is on the axis,the middle section (which is a double section having twice the number oftubes) is on the opposite side of the axis and the sections E and E aredisposed, re spectively, in the same manner as E and E.

As will be seen from the drawings, the tubes in each section or groupare parallel with each other, but the several groups are arrangedfan-wise, converging from the auxiliary drums C, C towards the steamdrum A.

This arrangement has the advantage that at the base of the triangle,where the furnace is cooler, the tubes are disposed, preferably, in asingle row, but they concentrate at the upper portion of the furnacewhere the heat is more intense to enter the upper drum in parallellongitudinal rows forming a bank of tubes, two, three or more rows indepth.

Downflow tubes F may be provided at each end of the tubes C, C".

The arrangement according to the invention not only protects the sidewalls of the combustion chamber against excessive heat but forms anextension of the space availabl for the gene 'ation of steam.

Tl10 application of the invention is not restricted to the three drumtype of boiler.

illustrated.

Although in the example illustrated there is only a single set ofauxiliary tubes at the auxiliary drun'is, two or more such sets may beprovided.

l-laving thus described the nature of the said invention and the bestmeans I know of carrying the same into practical effect. I claim i I 1.In a water tube boiler, an elevated steam and water drum, water drumsparallel therewith, inclined banks of water tubes connect in g saidwater drums with-the elevated steam drum, transversely disposedauxiliary water drums arranged parallel and adjacentto the lower partsof the side walls of the furnace, and water tubes connecting saidauxiliary drums with said elevated steam and Water drum, said Watertubes consisting of straight tubes arranged in groups, said groups beingarranged fanivise and converging from each auxiliary Water drum towardsthe elevated steam drum and the tubes of each group being parallel witheach other but inclined with respect to the tubes of adjacent groups.

2.91 Water tube boiler according to claim 1, wherein the tubes of eachof the several groups form at their lower ends a single row and suchrows are relatively staggered.

In testimony whereof I have signed my name to this specification.

HAROLD EDGAR YARROV.

